[U-Boot] [PATCH 08/10] x86: qemu: Add MP initialization

[Bin Meng]

The existing MP initialization process works on QEMU multicore,
except that we need increase delay time for BSP to wait APs to
show up online. Use a Kconfig option to control the delay time
factor to the normal one.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 arch/x86/cpu/mp_init.c           |  4 ++++
 arch/x86/cpu/qemu/Kconfig        | 11 +++++++++++
 arch/x86/dts/qemu-x86_i440fx.dts | 20 ++++++++++++++++++++
 arch/x86/dts/qemu-x86_q35.dts    | 20 ++++++++++++++++++++
 configs/qemu-x86_defconfig       |  4 ++++
 doc/README.x86                   |  5 +++++
 6 files changed, 64 insertions(+)

diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c
index e686b28..f87201b 100644
--- a/arch/x86/cpu/mp_init.c
+++ b/arch/x86/cpu/mp_init.c
@@ -75,6 +75,10 @@ static int wait_for_aps(atomic_t *val, int target, int total_delay,
 	int timeout = 0;
 	int delayed = 0;
 
+#ifdef CONFIG_QEMU
+	total_delay *= CONFIG_MPINIT_DELAY_FACTOR;
+#endif
+
 	while (atomic_read(val) != target) {
 		udelay(delay_step);
 		delayed += delay_step;
diff --git a/arch/x86/cpu/qemu/Kconfig b/arch/x86/cpu/qemu/Kconfig
index fb775d7..a690060 100644
--- a/arch/x86/cpu/qemu/Kconfig
+++ b/arch/x86/cpu/qemu/Kconfig
@@ -18,4 +18,15 @@ config SYS_CAR_SIZE
 	hex
 	default 0x10000
 
+config MPINIT_DELAY_FACTOR
+	int "QEMU multicore initialization delay factor"
+	depends on SMP
+	default 100
+	help
+	  During multicore initialization after BSP sends SIPI to wake up APs,
+	  U-Boot needs to wait some time for AP to show up online. The delay
+	  time is good for real hardware, but seems not enough for QEMU. The
+	  value of this option will be used as the multiplier to the normal
+	  delay time.
+
 endif
diff --git a/arch/x86/dts/qemu-x86_i440fx.dts b/arch/x86/dts/qemu-x86_i440fx.dts
index 0c522c8..e3c6fc3 100644
--- a/arch/x86/dts/qemu-x86_i440fx.dts
+++ b/arch/x86/dts/qemu-x86_i440fx.dts
@@ -24,6 +24,26 @@
 		stdout-path = "/serial";
 	};
 
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu at 0 {
+			device_type = "cpu";
+			compatible = "cpu-x86";
+			reg = <0>;
+			intel,apic-id = <0>;
+		};
+
+		cpu at 1 {
+			device_type = "cpu";
+			compatible = "cpu-x86";
+			reg = <1>;
+			intel,apic-id = <1>;
+		};
+
+	};
+
 	pci {
 		compatible = "pci-x86";
 		#address-cells = <3>;
diff --git a/arch/x86/dts/qemu-x86_q35.dts b/arch/x86/dts/qemu-x86_q35.dts
index 5fbabc2..0305864 100644
--- a/arch/x86/dts/qemu-x86_q35.dts
+++ b/arch/x86/dts/qemu-x86_q35.dts
@@ -35,6 +35,26 @@
 		stdout-path = "/serial";
 	};
 
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu at 0 {
+			device_type = "cpu";
+			compatible = "cpu-x86";
+			reg = <0>;
+			intel,apic-id = <0>;
+		};
+
+		cpu at 1 {
+			device_type = "cpu";
+			compatible = "cpu-x86";
+			reg = <1>;
+			intel,apic-id = <1>;
+		};
+
+	};
+
 	pci {
 		compatible = "pci-x86";
 		#address-cells = <3>;
diff --git a/configs/qemu-x86_defconfig b/configs/qemu-x86_defconfig
index a4c20bd..62c3f35 100644
--- a/configs/qemu-x86_defconfig
+++ b/configs/qemu-x86_defconfig
@@ -1,6 +1,9 @@
 CONFIG_X86=y
 CONFIG_DEFAULT_DEVICE_TREE="qemu-x86_i440fx"
+CONFIG_SMP=y
+CONFIG_MAX_CPUS=2
 CONFIG_GENERATE_PIRQ_TABLE=y
+CONFIG_CMD_CPU=y
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_FLASH is not set
 # CONFIG_CMD_SETEXPR is not set
@@ -9,6 +12,7 @@ CONFIG_BOOTSTAGE=y
 CONFIG_BOOTSTAGE_REPORT=y
 CONFIG_CMD_BOOTSTAGE=y
 CONFIG_OF_CONTROL=y
+CONFIG_CPU=y
 CONFIG_SPI_FLASH=y
 CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
diff --git a/doc/README.x86 b/doc/README.x86
index 5d71244..1cab42c 100644
--- a/doc/README.x86
+++ b/doc/README.x86
@@ -281,6 +281,11 @@ QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
 show QEMU's VGA console window. Note this will disable QEMU's serial output.
 If you want to check both consoles, use '-serial stdio'.
 
+Multicore is also supported by QEMU via '-smp n' where n is the number of cores
+to instantiate. Currently the default U-Boot built for QEMU supports 2 cores.
+In order to support more cores, you need add additional cpu nodes in the device
+tree and change CONFIG_MAX_CPUS accordingly.
+
 CPU Microcode
 -------------
 Modern CPUs usually require a special bit stream called microcode [8] to be
-- 
1.8.2.1